SIPS & Bloated File Size

As some of you may know, FireFox 3.5 now supports color management. Great for photography, not so much for web graphics that we mistakenly exported with SRGB which now do not match hex colors.

I have written a script that strips the color profile via SIPS:

set cmdline to ("sips -d profile --deleteColorManagementProperties " & filePosixPath) as string
do shell script cmdline

This works as expected. The only down size is that it adds to the overall file size. A 130k large bg image is now prfile free but at 150k. SIPS must be doing something when updating the image that is adding the weight. Anyway to make it stop the bloat or strip what it adds after it strips the profile?